GREEN BAY - Fall is just getting started and winter may be months away, but advertisements urging people to get their flu shots have begun popping up at drug stores everywhere.

Is now really the right time to get vaccinated, though?

Most medical professionals agree it is better to get the flu shot than not to get one. However, there are differing opinions on the best time to get the vaccine in order to ensure effectiveness and that consumers get their money's worth.

According to the Centers for Disease Control, flu activity in the United States peaks between December and February. The CDC and the Advisory Committee on Immunization Practices recommend flu vaccinations begin by the end of October, if possible. The CDC also suggests everyone 6 months and older get vaccinated.

Carol Bess, infection prevention coordinator at Bellin Hospital, said it's not unusual, though, for healthcare providers and pharmacies to start promoting the vaccine months in advance so people actually remember to get vaccinated. As far as getting vaccinations, Bess said, the sooner, the better.

Edward Bantamoi, family medicine physician at Prevea Ashwaubenon Health Center, takes a different approach. He said he tells his patients to get vaccinated in November if possible because research shows the vaccine is most effective during the first 100 days after it is administered.

"After 120 days, it is essentially 0 percent effective," he said.

Historically, Bantamoi said, February is the month with the strongest flu symptoms. So, if patients get vaccinated in November, the better the chances they will able to get through the most crucial months of flu season without getting sick.

The CDC estimates this year's vaccine will be 59 percent effective. Last year's was less than 23 percent effective.

Bess said patients should keep in mind that everyone's body reacts differently to the vaccine, and that it is impossible to know exactly when and how hard the flu is going to hit communities. For example, an individual could unknowingly be exposed to the flu during any month, get the shot the next day and still become ill. In this situation, it is not that the shot is ineffective. Rather, being exposed to the virus before the vaccine was administered is what is causing problems.

These possibilities should not deter people from getting vaccinated, though. Bess and Bantamoi said individuals who get vaccinated every year are in the best shape when up against the flu of any strain. Bantamoi said elderly people who receive the flu shot annually reduce mortality by 47 percent.

There are several types of flu vaccines, each designed for certain people. The experts suggest patients do their research and consult their doctor to determine the type of vaccine that will work best for them.